Question

A cheetah of mass 68 kg can accelerate from rest to a speed of 20.1 m/s in 2.0 s. Assuming constant acceleration, what is the net force that causes this acceleration?

272 N
78 N
137 N
680 N

Answer 1

680 N

Step-by-step explanation:

We start by calculating the cheetah's acceleration knowing that goes from rest (0 speed) to 20.1 m/s in 2 seconds:

`a=(v_f-v_1)/(t) \\a=(20.1-0)/(2) =10.05 (m)/(s^2)`

Now we use the definition of force (F):

`F=m*a\\F=68 kg * 10.05 (m)/(s^2) =683.4 N`

Therefore the force that accelerates the cheetah is 683.4 Newtons which we can round to 680 N to match the fourth choice shown